This invention relates to a method for face-to-face weaving pile fabrics whereby warp yarns of a series of warp yarn systems are interwoven with weft yarns so that a top and a bottom backing fabric are formed, whereby pile warp yarns are alternately passed around a weft yarn of the top backing fabric and around a weft yarn of the bottom backing fabric so that they form pile, while per warp yarn system at least two non-pile-forming pile warp yarns are inwoven in one and the same backing fabric, and whereby the pile-forming pile warp yarns are split between the two backing fabrics so that two fabrics are obtained.
This invention also relates to a pile fabric comprising a backing fabric woven out of weft yarns and warp yarns, a number of pile yarn loops passed around weft yarns of the backing fabric and pile warp yarns inwoven in the backing fabric, and more especially such a pile fabric that is woven according to the method according to this invention.
The above described known method can be implemented on a known weaving machine which is provided for inserting one or several weft yarns between warp yarns in the course of successive weft insertion cycles. These warp yarns are for that purpose positioned in relation to the weft insertion levels by means of a shed-forming device.
The warp yarns are provided in a series of warp yarn systems located next to one another, and the warp yarns of each warp yarn system are pulled through a respective space between reed dents. Per warp yarn system several pile warp yarns are provided, for example in order to allow differently colored pile warp yarns alternately to form pile and be inwoven in accordance with a predetermined pattern, so that the differently colored pile loops of the fabric form the pattern.
The demand for pile fabrics with a wide color variation is increasing and the development of such fabrics is becoming evermore easy by the use of CAD systems and electronic jacquard machines. For this purpose per warp yarn system a large number of differently colored pile warp yarns must be provided. If the number of pile warp yarns per warp yarn system, also called xe2x80x9cthe number of pile frames per reed spacexe2x80x9d, is high (for example 6 or higher) they are called pile fabrics with high frame count. In each warp yarn system there are a number of pile warp yarns that form no pile and are burried in one of the backing fabrics. It is usual to divide these non-pile-forming pile warp yarns between the top and the bottom backing fabric for their inweaving. As long as the number of pile warp yarns per fabric to be inwoven remains limited, pile fabrics of a high quality can be woven in the known manner. But with pile fabrics with high frame count, drawback effects occur with color transitions in weft direction. If namely in two warp adjacent yarn systems with several different pile warp yarns provided next to one another in a specific sequence a pile warp yarn of different frame has to form pile, it is possible that a large number of inwoven pile warp yarns extend between the two pile-forming pile warp yarns running next to one another and push apart the pile loops formed by these pile warp yarns. Because of this with a number of color transitions in weft direction a line becomes visible extending in warp direction. Such a fabric is clearly of a lesser quality.
In order to remedy for this drawback a number of measures have been put forward in the Belgian patent application no. 9700712. These measures reduce the drawback effects with color transitions in weft direction but appear in general, and especially with fabrics where a frame count of 8 or more is used per warp yarn system, insufficient for obtaining fabrics of a perfect quality.
The purpose of this invention is on the one hand to provide a face-to-face weaving method that enables pile fabric weaving of a perfect quality, and this not only where the frame count per reed space is relatively low (at least two), but also where this frame count is particularly high (e.g. 12, 14 or more), and on the other hand to provide a pile fabric with such properties that the quality thereof is independent of the frame count per reed space, in contrary to the known pile fabrics.
These objectives are achieved according to this invention by means of a method with the characteristics mentioned in the first paragraph of this specification, whereby the aforesaid non-pile-forming pile warp yarns are divided per warp yarn system into at least two groups each with at least one pile warp yarn, and whereby the pile warp yarns of the different groups extend respectively at a different level in the same backing fabric, and by providing a pile fabric comprising a backing fabric woven out of weft yarns and warp yarns, a number of pile yarn loops passed around weft yarns of the backing fabric and pile warp yarns inwoven in the backing fabric, of which the inwoven pile warp yarns divided between at least two layers located one above the other are inwoven in the backing fabric.
Because of the fact that the inwoven pile warp yarns are divided per warp yarn system between two layers located one above the other a series of inwoven pile warp yarns between two pile loop rows no longer occupy such a large width as with fabrics that are woven according to the known weaving methods. Because of this the pile loops are not spread apart and the drawback effect of line formation is prevented, in pile fabrics with high frame count.
According to a preferred method according to this invention the pile warp yarns of different groups inwoven in the same backing fabric are separated from each other by weft yarns of the backing fabric.
This method according to the invention is preferably so implemented that each group comprises at least two pile warp yarns.
It is furthermore also preferable in each warp yarn system per group of pile warp yarns to inweave a tension warp yarn adjacent to these pile warp yarns.
According to a particularly efficient method in each backing fabric weft yarns are inwoven at three different levels, namely a pile side level, a middle level and a back level, and in each backing fabric per warp yarn system a first and a second group of pile warp yarns are inwoven, respectively running along the pile side and along the backside of the middle level weft yarns.
This method can also be so applied that the pile warp yarns of the first group run between the weft yarns of the pile side level and the weft yarns of the middle level, while pile warp yarns of the second group run between the weft yarns of the middle level and the weft yarns of the back level.
The pile warp yarns of the first group can also be undulatingly inwoven, whereby in each warp yarn system they alternately run along the pile side in relation to a weft yarn of the pile side level and between a weft yarn of the pile side level and a weft yarn of the middle level.
The most preferred is the method according to this invention whereby in each backing fabric alternately two weft yarns one above the other and one single weft yarn are inwoven, whereby the two weft yarns inwoven one above the other are inwoven in the backing fabric respectively at the middle level and at the back level, and whereby the single weft yarns are inwoven in the backing fabric at the pile side level.
The non-pile-forming pile warp yarns are moreover preferably also inwoven divided per warp yarn system between the top and the bottom backing fabric.
This method has the greatest productivity if it is utilized on a weaving machine with weft insertion means that are provided for inserting simultaneous three weft yarns between warp yarns per weft insertion cycle.
According to another particular property of the method according to this invention in each backing fabric a first, a second and a third binding warp yarn is provided per warp yarn system, so that the first and the second binding warp yarn cross each other repeatedly and an opening is formed in each case between every two successive intersections, through which two weft yarns extend one above the other, and so that the third binding warp yarn runs alternately along the pile side in relation to a weft yarn of the pile side level and along the back in relation to a weft yarn of the middle level.
A pile fabric, comprising a backing fabric woven out of weft yarns and warp yarns, a number pile yarn loops passed around weft yarns of the backing fabric and pile warp yarns inwoven in the backing fabric, of which the inwoven pile warp yarns are inwoven divided between at least two layers located one above the other in the backing fabric, is another object of this invention. The quality of such a fabric is perfect, even if the warp yarn systems comprise a large number of pile warp yarns. In pile fabrics with high frame count and with color transitions in weft direction no trouble lines are formed any longer.
With such a pile fabric the pile warp yarns of different layers can be separated from each other by interjacent weft yarns, and the inwoven pile warp yarns can be divided per warp yarn system between the aforesaid layers while in each warp yarn system a tension warp yarn is married to each layer of pile warp yarns.
Furthermore each pile fabric that is manufactured according to the method according to this invention is of course also a pile fabric according to this invention.
The characteristics and advantages of this invention are further explained on the basis of the following detailed specification of a possible method according to this invention and of the fabric manufactured according to this method. This specification is only given by way of example and can consequently in no way be interpreted as a restriction on the scope of the protection claimed for this invention in the claims of this patent application.
In this specification reference is made to the drawing attached hereto,